Crankshaft / Transmission

Crankcase disassembly

With the engine out, first strip the cylinders, pistons, camshafts, balancer, external shift mechanism, clutch, alternator rotor, oil filter and oil pan (see their chapters).

1. 1

   Loosen the transfer-gear nuts on the output and pulley shafts (hold with the gear holder 57001-1574) and remove the transfer gears.

   The output-shaft transfer-gear nut has left-hand threads — turn it clockwise to remove.

2. 2

   Remove the rear balancer sprocket bolt (hold the rear balancer gear with the flywheel & pulley holder), then the oil-pump chain tensioner, spring, tensioner, chain and rear balancer sprocket; remove the pulley-shaft collar and O-ring.

3. 3

   Remove the left then the right crankcase bolts — φ8 bolts first, then the twelve φ6 bolts each side.

4. 4

   Turn the right crankcase down, lift the left half off, and split the halves only at the front and rear pry points.

   ▲ Caution

   Use only the cast pry points — prying elsewhere mars the sealing face and ruins the matched set.

5. 5

   Lift the balancer shafts, crankshaft, transmission gear assembly, pulley shaft and water-pump shaft from the right half; take the oil-pump shaft and relief valve from the left half.

Crankcase assembly

Clean both mating faces with a high-flash-point solvent, blow the oil passages clear, and press in any new bearings supporting the boss.

1. 1

   Press new bearings/races in until they bottom, supporting the crankcase bearing boss; fit oil seals with the spring side of the lip toward the inside of the case.

   ▲ Caution

   Support the bearing boss when pressing, or the crankcase will be damaged.

2. 2

   Fit the bearing retainers, install the relief valve with locking agent and torque it.

   Torquerelief valve 9.8 N·m
3. 3

   Apply moly oil to the transmission gears, ball bearings, shift drum and crankshaft main bearing, then set the crankshaft (its left shaft is the longer one), balancers, transmission assembly, shift forks/rods, pulley and water-pump shafts into the right half; the right con-rod goes forward, the left con-rod rearward.

4. 4

   Install the front & rear balancers with their splined ends downward and the pulley shaft with its short flange-to-end side downward; grease and fit the O-ring and confirm the dowel pins are seated.

5. 5

   Apply liquid gasket (Kawasaki Bond 92104-1064) to the left half’s mating face — including the lower ends, but keep it out of the oil passages — then fit the halves and torque the bolts within 20 minutes: φ8 bolts first, then φ6.

   Torqueφ8 29 N·m · φ6 12 N·m

   Tighten each size temporarily first, then to final torque; wipe up any gasket that squeezes out.

6. 6

   Confirm the crankshaft, both balancer shafts, the oil-pump and water-pump shafts, and the drive, output and pulley shafts all turn freely; refit the transfer gears.

Connecting-rod removal & installation

1. 1

   Mark and record the position of each connecting rod and big-end cap (leave the inserts attached) so they go back exactly where they came from.

   ▲ Caution

   Do not let the rod bolts knock the crankpin surfaces — even small dings ruin the journal.

2. 2

   On installation, apply moly oil to the inside of the inserts; if fitting new inserts, keep moly oil off their backs and the rod/cap bore, and seat the insert nails on the same side into the recess.

3. 3

   Fit each cap aligning the diameter mark, with the “OUT” marks facing outward — the left rod is the rear cylinder, the right rod the front.

4. 4

   Apply moly oil to the big-end bolt threads and flanges and torque them.

   Torquebig-end bolts 59 N·m

Connecting-rod & crankshaft inspection

1. 1

   Bend & twist: with an arbor through the big end on a V-block, measure bend (rod vertical) and twist (rod horizontal) over 100 mm. Replace the rod if either exceeds TIR 0.2/100 mm.

2. 2

   Big-end side clearance: insert a feeler between the big end and a crank web. Standard 0.08–0.30 mm; replace the rod (then re-check, and the crankshaft if still loose) past 0.5 mm.

3. 3

   Big-end bearing clearance: plastigage on the crankpin, torque the cap to 59 N·m, measure. Standard 0.026–0.057 mm; 0.057–0.10 mm → fit blue inserts; past 0.10 mm measure the crankpin (limit 54.97 mm) and replace the crankshaft if worn.

4. 4

   Crankshaft runout (TIR 0.15 mm limit), main-journal diameter (56.96 mm limit), main-bearing/journal clearance (0.10 mm limit) and side clearance (0.55 mm limit) — replace the crankshaft, or the matched crankcase halves, as the limits direct.

Balancer timing on installation

1. 1

   Align the timing marks on the balancer chain sprocket and the front & rear balancer sprockets with the coloured chain links.

2. 2

   Fit the sprockets by matching their wide grooves to the wide teeth on the crankshaft and the front & rear balancer shafts.

3. 3

   Fit the shaft washers, and the crankshaft washer with its “OUT SIDE” mark facing outward, then tighten the chain sprocket nut and the sprocket bolts.

   Torquechain sprocket nut 125 · sprocket bolts 83 N·m

   Apply moly oil to the chain-sprocket-nut threads & seat.